Cellulose esters containing unsaturated organic acid groups



- I oDrawing.

Pears-Na. 6, 1923.

PATENT- 1 oer-ice.-

{we 'r. cmim am) can. .1. mar, or means ma, new you, nssienons 'ro mnum xon'ax mm, or nocnns'rnn, NEW Your, a oonronarron. or raw YORK.-

1 cnLLULosn ns'rnas conramnve unsaruna'rnnonemrc 4cm oaours.

lpplicatio'n filed Iay This invention relates to cellulose esters containing unsaturated organic acid'groups.

One object of the invention is to provide es ters containing such groups, whether they be the sole acyl roups. 1n the esteror whether saturated .acy groups be present along with the unsaturated ones. Another object of the invention is to provide esters ofthischaracter which are soluble'in useful or'ga'nicneutral solvents, and ield-transparent films,

many of them high y flexible. Another-ob I ject of the invention is to provide cellulose esters containingan unsaturated acyl group,

in which substitutions may be readily made.

Other objects will hereinafter appear; 5

so far aswe are'aware', cellulose esters of unsaturated organic acids have hitherto not 7. the acyl groups consist so ly of the unsatubeen described', especially esters-having useful solubilitiesin 'or anic solvents. We have found that useful ce ulose esters, having use- ;ful solubilities, maybe prepared which contain an-acyl group corresponding to amonocarboxylic unsaturated organic acid in'which there -is an 'e'thylenic bond. We have also found that esters may be repared in. which rated species, or part of-the acyl'groups may be unsaturated, and

varnish making materials, but they serve as extremely valuable intermediates m the manufacture of 1 further compounds by atv tacking-or substituting 'in the unsaturated ac l'groups;

he unsaturated acyl groups which best serve our purposes are those in the series of acids beginningwith acrylic and those which 5 =cinm unic acid, .40 parts by wei q fi; anhydrid and s' mf i p I ex pt asfindicated in sw 1 Pen c ims.

I may be consideredas derived *from them 'by tonicand undecylenicare representatives of a the lower andhi substitution, such i-as. cinnamic acid. Pf, the acids in the series beginning-withacrylic, croer members, and will be used,'fltherefore, "mi the following illustrations; but. it. understood that our in-. vention is n'o'tlimited to these illustrative the,res't: saturated. Not only do these esters'constitute useful film and cellulose mews 1937. Serial R9. 188,862..

65; 0. until the fibers disappear and a more 7 or less clear dope is obtained. This may take say about 5 hours. From the reaction mass thecel-lulose cinnamate is obtained by precipitationin methyl alcohol,-and washing with the s a me The'product is soluble in chloroformand from its solution yields transparent films or varnish layers. In anot r example, 5 parts by weight of the above mentioned tissue paper is added to a nnxture of parts by weight of crotonic acld, 3.0 (parts by weight of chloroacetic anhydrid an perchlorate. The thoroug lymixed reaction mass i's'kept at 60 to 65 C. until the fibers largely dope 1s obtained.- This generally occurs in about 5 hours. The cellulose crotonate is ob tained from @the reaction mass by precipitat1on with a aqueous methyl alcohol solution and washed with the same liquid. The product, when dried, is soluble in acetone, chloroform, benzol, or mixtures of these. Its solutions yield trans arent films. f

Instill another i ustration of our invention 10 parts byweight of tissue above kind is, added to amixture o 40 parts by weight of crotonic acid, 30 parts by weight of acetic anhydrid 30 parts of chloroacetic ac d and 0.1v art by wei ht of magnesium .7 perchlorate. mass is kept at to C. until the fibers dis- .05 parts by wei ht of magnesium disappear, and amore or less clear e0 paper of the he thoroug ly mixed reaction appear andadope is obtained. The latter is i precipitatedinto methyl alcohol; and the ester washed with liquid. The cellulose acetosolutions are spread and evaporated, colloid- I ized films are 0 tained which are-transparent and flexible. 7 Y

The relative-proportions of theesteri ing baths may be varied to obtain products aving difierent proportions of saturated and unwhen saturated acyl oups.-' For example i acetic it is desired. t increase the amount 0 acid grou s, and lower the amount of crotonic grou s, t e procedure may, for instance,.-be

as f0 ows: 5 rts by weight of'clean cotton cellulose, pre erably. in t e form of tissue paper, 1s added to a mixture of 12 parts by ."mtue and News we ght ofcrotonic acid, 15 parts by wei ht of acetic anhydrid, 15 partsb weight ofjc f oro- 'nesium perchlorate. The mixture is kept at 60 to 65 C. until a fairly. clear dope is obtained by the disappearance of the cotton fibers. This often takes about 5 or '6 hours. The ester is recovered from the reaction mass by precipitation in 50% aqueous methyl alco-.

- hol and the product washed with thisliquid.

The product issoluble in either chloroform, or acetone, or mixtures of them. From its solutions it gives transparent, colloidized, flexible films. p r I In still another example of our invention 5 parts by weight of the special tissue paper liereinabove mentioned are added to a mix- 3 ture of parts by weight of crotonic acid,

15 parts by weight of acetic anhydrid, and

0.2 parts by weight of cop e'r perchlorate, and 22 parts by weight of c loroform. The

- mixture is warmed at 60 to 65 C. until a dope is obtained, say in about 28 hours. The, cellulose aceto-crotonate is recovered fromthe mass by precipitation with methyl {alco hol, washing with the sameli uid and drywhich are transparent and flexible.

ing. It is soluble in either 0 oroform or acetone, or mixtures of theln, and 'elds from such solutions films 0r varnish ayers .In another form of our invention parts by weight of rayon fibers prepared by the.v cuprammonium process are placed in 'a'mix 'ture' of 300 parts 'byweight of crotonic acid and parts by weight of chlorobenzene. The mixture is heated for 48 hours at 155 to 157 C. During thisriod the'chlorobenzene may be distilled o at intervals and replaced by further d chlorobenzenei. This removes the water whlch is present or formed during the reaction. The rayon fibers which are now lower cellulosic esters ofcrotonic -ac'id,-are filteredofi from theother ingrediants and washed with methyl alcohol. 5

parts by weight of these. prepared fibers are then added to a mixture 0 rid and the mixture warm 30 parts by weight of acetic acid, 20 parts by weight of acetic 'anhyd'rid and 1 part by wei ht "of zinc chloat '60 to C.

until a homogeneous dope is. obtained. From water and 'washin alcohol The p this reactionmixture the cellulose acetocrotonate is obtained by precipitation with with water "or methyl act is soluble in chloro-.

' form or acetone, or mixtures of'the'm and "elds flexible, trafisparentor varnish mercerized for 48 hours at room tem ayers. In stilla furtherform of ourinveution 20 parts by? weight of long fibered cottoltimii;

in an 18% aqueous sodium hydroxide solu ti'ou. 1 At the-fend of this period it is washed freefrom alkali water and then the water is removed by washing with a mix-.

7 ture ofsubstantially anhydrous-alcohol and ether. Finally it is dried in th tioned' surfaces, thus pmduced, are

hydrid, and .05 parts heated in a boiling mixture of 500 parts by weight of crotonic acid and 100 parts by weight of chlorobenzene, thetemperature being at about 155' to 157 C. The water lib- 'erated by the esterification reaction is periodically removed by distillatiomthe chlorobenzene which distills off, being replaced with dry chlorobenzene. this treatment the fibers contain considerable amountsof crotonic groups esterifiedonto the cellulose, althou h in this condition, of course, the esterification has not been carried far enough to produce useful solubility. The

After 48 hours of lower cellulose crotonates, thus-formed, are

then acetated. For example, 5

parts by weight of them are treated in a mlxture of 3 15 parts by weight of acetic anh drid, 20 parts by wei ht of acetic acid, an 0.1 art by weight 0 magnesium perchlorate. reaction is conducted at 60 to 65 C. and the cellulose aceto-crotonate, thus produced, isolated by scribed a ove. The product is so vble in chloroform, and yields transparent films. The proportion of crotonic groups in the ester may be increased b carrying the .boil-. ing of the mercerizedfi ers in the crotonic acid-chlorobenzene mixture for 96 hours.

recipitatingand washing as de-- This gives a product containing'more crotonicgroups, and consequently when such lower cellulose cretonates' are acetated, as

above described, the'percentage of unsatu 01' part by weight of magnesium perchlorate.

This is heated at 60 to 65 C. until a homo geneolis dope" is obtained, say inabou't 20 :isp'oured into methyl alours. ThlS do cohol to' precipitate the cellulose crotonostearate, and the product is washed with warm methyl alcohol and dried. It is soluble in chloroform,:acetone, 1, or mix tures of these. From its .so utionsit'yields m es ee transparent colloidized flexibllity.

In sti another illustration ofour inven tion. 5 parts by weight of tissue paper, of the kind described above, are stirred mto a mixture of 15.- parts by wei ht of nudecylenic acid, 25"parts by weig t of. chloroacetic acid, 15 parts -bweight of acetic anwelght c n ma- 0 unl massisthenkeptalt60to65 iao homogeneous dope is obtained, say in about 6 hours. This dope is treated wlth methyl alcohol to precipitate the cellulose aceto-undecylenate. The product is soluble in either chloroform or acetone, or mixtures of them. a While in the above examples, in which 'mixedesters are produced, we have mentionedonly acetic groups and stearic groups from the fatty acid series, it will be understood that groups corresponding to any 'ofthe other acids of the fatty acid monocarboxylic series may likewise be emplo ed.

It is interesting to note that mixe esters having approximately 12 acyl groups for every 24 carbon atoms in the cellulose, become acetone soluble when at least one and one-half of the acyl groups are crotonie and] the rest acetic; or when slightly more than one-halfa group is undecylenic and the rest acetic. In general it will be seen that the number of unsaturated groups on such a basis is obtained by dividing six by the number of carbon atoms in the unsaturated acid. I Our novel unsaturated esters may be mixed With other cellulose esters which are soluble in the same solvents, such as celluloseacetate and/or cellulose nitrate either with or without plasticizers.' Thus films may be prepared from. such dissolved mixtures. La ers of our unsaturated esters may likewise e combined with layers of the cellulose esters or ethers in laminated'films or other products,

a common solvent being present to promote E the adherence of the layers in accordance with customary laminating practice. For example, a film of our unsaturated esters may have a very thin layer of somewhat hygroscopic' cellulose acetate, on its rear face,-. that is, the face opposite the one which re ceives' the photographic emulsion.

In plastic or flowable compositions in which our unsaturated esters form an emential con-- stituent, there 'may also be present anyof day of April, 1927.

the substances of. low volatility commonly colloidized with cellulose acetate in its known compositions, a suitable amount of a common solvent, such as acetone, chloroform, or ben- -zol, or mixtures of them being used. Moreover, the proportions may be approximately the same as those heretofore employed in connection with cellulose acetate.

Our unsaturated esters may be used in making any of the things hitherto made by employing the' previously known cellulose esters. An incomplete but suggestive list of such uses includes'molded artlcles, varnishes I 3. A' cellulose ester in which a cellulose group is esterifiedwith'a crotonic group.

4. A mixed organic ester of cellulose, in which a cellulose group \is. esterified with both a fatty acid group and anacyl group corresponding to a monocarboxyhc organic acid in which there is an ethylemc bond.

5. A mixed organic ester .of cellulose in which a cellulose group is esterified with both' a fatty acid group and an acyl group corresponding to an acid of the acrylic series. 6. Cellulose crotono-stearate. Signed at Rochester, New York, this 27 th HANST. CLARKE. CARL J. MALM. 

